In a message dated 99-07-07 00:45:00 EDT, bpremack@WAVETECH.NET writes:

<< Your 91 should have the fiberglass bumper covers.  Remove these by taking
 out a few simple bolts (hidden under some plastic caps, if I remember
 correctly).  You will then see a mammoth closed box frame steel member which
 is the real front bumper.  (This bumper is the same for all Vanagons,
 regardless of the outer bumper or year.)

 It conveniently has 2 sets of holes about 2/3 of the way out from the
 center, one set on each side.  The holes are about 2 1/2 inches apart.  If
 you get the right size u-bolt and run it through each set of holes, you can
 then attach a tow bar to the u-bolts.  Be sure to use hardware adequately
 sized for the job. >>

or you could just rent a tow dolly from U-Haul for $35-$40  ;<)

chris